L. P. Olekhnovich

Dipolar spirocyclic σ-complexes based on of 4,6-dinitrobenzofuroxan

The first dipolar spiro-σ-complexes with a superelectrophilic dinintrobenzofuroxan fragment and tropolone systems with diastereotopic substituents were synthesized. The kinetics of their enantiotopomerization, which occursvia cleavage-formation of the Cspiro-heteroatom bond, was studied by dynamic1H NMR. The stereorigidity of dinitrobenzofuroxan spiro-complexes in this degenerated process increases in the series: tropolone<aminotropone<aminothiotropone≈aminotroponimine. The two last posses the highest kinetic stability compared to all known zwitterionic spiro-complexes.

3,4-DIACETYLHEXANE-2,5-DIONE : AN EFFECTIVE SYNTHON FOR SYNTHESIS OF SUBSTITUTED AZULENE HETEROANALOGS BY CYCLOCONDENSATION REACTIONS

The one-pot method for the synthesis of 4,8-dialkoxy-6-aryl-1,3-dimethylcyclohepta [c]furanium perchlorates has been developed. The method is based on the cyclocondensation of 3,4-diacetylhexane-2,5-diones with aromatic aldehydes and trialkyl orthoformates under the action of a 16% perchloric acid solution in acetic anhydride. Under similar conditions, with hydrogen sulfide, cyclohepta[c]thiophenium perchlorates have been obtained, while cyclohepta[c]pyrrolium perchlorates have been prepared with arylamines, ammonium acetate, or aliphatic amine acetates. A heteroanalog of azulene, 4,8-diethoxy-1,3-dimethyl-2-azaazulene, has been obtained for the first time. Hydrolysis of aza- and thiaazulenium salts gives the corresponding cyclohepta[c]pyrrol-4-ones and cyclohepta [c]thiophen-4-ones.

Synthesis, structures, and properties of spiro[6-azaperimidine-2,4′-cyclohexa-2′,5′-dien]-1′-one derivatives

The reaction of 5-amino-4-chloroquinolines with 4-amino-2,6-di-tert-butylphenol yielded derivatives of spiro[6-azaperimidine-2,4′-cyclohexa-2′,5′-dien]-1′-one, which exhibit photo-and thermochromic properties in solutions. The structure of 2′,6′-di-tert-butyl-5,7,9-trimethylspiro[6-aza,-2,3-dihydroperimidine-2,4′-cyclohexa-2′,5′-dien]-1′-one was established by X-ray diffraction study. The ring-chain isomerization of 2′,6′-di-tert-butyl-5,7-dimethyl-and 2′,6′-di-tert-butyl-5,7,8-trimethylspiro[6-aza-2,3-dihydroperimidine-2,4′-cyclohexa-2′,5′-dien]-1′-ones was studied by dynamic NMR spectroscopy.

Cation radicals of N,N1'-diarylbenzamidines

Conclusions1.Protonation of N,N-di-p-tolyl-(3,5-di-tert-butyl-4-oxylphenyl)amidinium radical leads to the formation of a cation radical similar in structure to amidinum salts with an s-cis and s-trans-arrangement of the p-tolyl groups relative to the phenoxyl group.2.Cation radicals formed by protonation of N,N-di-p-tolyl-N-acetyl-(3,5-di-tertbutyl-4-oxyphenyl) amidinium and N,N-di-phenyl-N-p-tolyl-(3,5-di-tert-butyl-4-oxylphenyl)amidinium radicals have a symmetric structure with inclusion of the carbonyl C atom and the phenyl ipso C atom in a four-membered 1,3-diazetidinium ring.

Properties of the triplet states of bipolar spiro-σ-complexes

Conclusions1.The triplet states of bipolar spiro-σ-complexes of tropolone derivatives possessing electron-donor and electron-acceptor properties were recorded.2.The reaction of the triplet states with strong electron donors in a nonpolar medium leads to the formation of triplet exciplexes.